The invention relates to a connection piece for a heat exchanger having a metallic header tank, the connection piece being capable of being soldered or preferably brazed to the header tank.
Heat exchangers having metallic header tanks and connection pieces, that are brazed to one another, are known, primarily, as so-called nonferrous metal radiators, the coolant tanks of which consist of brass. However, as a rule, modem aluminum radiators have plastic coolant tanks, onto which the connection pieces are already integrally molded in one piece. These plastic connection pieces are connected to the coolant hoses by means of a hose coupling. A seal is provided between the coolant hose or hose coupling and the connection piece, and a retaining means is also provided. These connection pieces therefore have, to some extent, complicated shapes that, however, can usually readily be produced by injection molding. Recently, however, the plastic tanks have been displaced by metal tanks, since radiators are nowadays often produced from aluminum as so-called all-metal radiators, that is to say including the coolant tanks and the connection pieces. A problem arises when the connection between connection piece and hose coupling no longer consists of two plastic parts, but of a metallic connection piece and a conventional plastic hose coupling.
It is therefore one object of the invention to provide an improved metallic connection piece for a heat exchanger, that can be used for a plastic hose coupling.
In particular, it is an object of the invention, in the case of a metallic connection piece, to provide an anti-twist retaining means for the hose coupling.
Another object of the invention is to provide an improved connection structure for a heat exchanger having a metallic coolant tank, as well as an improved heat exchanger having a hose connection.
In accomplishing at least one of these objects, there has been provided in accordance with one aspect of the present invention a metallic connection piece for a heat exchanger having a metallic header tank, the connection piece being capable of being brazed to the header tank, wherein the connection piece comprises: a) a connecting region for the header tank; b) a stop region formed by a continuous collar; c) a retaining region formed by a groove; and d) a sealing and centering region formed by a cylindrical part that merges into a conical part, where regions a)-d) adjoin one another in the direction of the longitudinal axis of the connection piece. Preferably, the stop region comprises a double bead, and one bead has integrally formed on it at least one anti-twist retaining protrusion that projects beyond the diameter of the bead.
In accordance with another aspect of the invention, there has been provided a connection structure for a heat exchanger having a metallic header tank and adapted for accepting a hose coupled thereto, the connection structure comprising: a connection piece as outlined above; a plastic sleeve placed axially over the connection piece; a sealing ring contained between the cylindrical part of the sealing and centering region and the inside of the plastic sleeve; and a retaining strap positioned in the groove of the retaining region; wherein the plastic sleeve comprises at least one axial groove for receiving the anti-twist retaining protrusion.
According to yet another aspect of the invention, there has been provided an improved heat exchanger having a metallic coolant tank and embodying the connection structure set forth above.
Further objects, features and advantages of the present invention will become apparent from the detailed description of preferred embodiments that is set forth below, when considered together with the accompanying figures of drawing.